Associative Cortex (brain): Types, Parts And Functions
We see, we hear, we smell, we touch… Human beings receive a large number of different stimuli that we experience through the senses. However What our sensory receptors capture is only raw data which by themselves would not help us survive.
For example, if we were not able to link visual perception with the feeling of threat, a predator could easily devour us. Nor would we be able to compose a melody, or enjoy a kiss. Even if we talk only about a perception and focus it only on one sense, we would not be able to give it a meaning.
We need to be able to gather the perceived data and integrate it so that it makes sense. Different nuclei such as the thalamus are responsible for this, as well as brain areas such as the associative cortex This article will discuss the latter, focused on exploring the types, functions and lesions associated with the associative cortex and its parts.
We call the associative cortex the part of the cerebral cortex (the most external and visible part of the brain) mainly responsible for associating and link together the different information from brain regions in charge of the various senses or having the necessary programs to carry out the movement.
In other words, these are the areas of the cerebral cortex that allow us to integrate information from the same sense and/or from several so that we can have a joint perception of the stimuli and the environment. Thus, they are the ones that broadly allow us to be aware of what surrounds us and even of ourselves, since Thanks to them we can interpret reality and react adaptively to her. The information processed can be sensory or motor.
There are different types of associative cortex depending on the type of information they process.
1. Unimodal associative cortex
The unimodal association cortex is responsible for processing information from a single sense or in order to perform a single function (such as movement). These cortices are generally located near the regions that process information from the senses or information necessary to move.
These are those areas that are linked to the processing and integration of sensory or motor information They allow, among other things, the recognition and interpretation of stimuli.
2. Multimodal associative cortex
This type of cortex is responsible for integrating information from different sensory modalities, allowing the interpretation of the environment and the planning and execution of mental operations or behaviors.
3. Supramodal associative cortex
This type of associative cortex differs from the previous ones in that it does not directly work with information from any sensory modality, but instead is linked to cognitive aspects It is often considered multimodal.
Main unimodal associative areas
The number of areas and associative structures is very high, due to the need to integrate the information that comes from the brain and act accordingly. In fact, it is considered that more than 80% of the cerebral cortex performs some type of association function.
If we talk about unimodal association areas, we can find the following among them.
1. Secondary visual area
Visual information is integrated in this brain region, linking aspects such as color, shape or depth
2. Secondary auditory area
Thanks to it we are able to integrate auditory information, such as pitch and volume
In this area, the perceptions from someesthesia are integrated, the set of sensations that we capture from our own body
4. Premotor area and supplementary motor cortex
Motor-type associative areas dedicated to the integration of the signals necessary to prepare an action or behavior. It has the necessary programs to carry out a movement
Three major areas of multimodal and supramodal association
Regarding the multimodal and supramodal association areas, in general we can indicate the existence of three large brain areas.
1. Prefrontal associative cortex
Located in front of the motor cortex, the prefrontal cortex is one of the brain areas most closely linked to the control and management of behavior, being largely responsible for how we are. It is mainly responsible for cognitive and behavioral management tasks, including aspects such as reasoning, prediction and planning, decision making or behavioral inhibition
Therefore, the set of executive functions, as well as the formation of the personality of each of us, originate from this area. Thanks to it we are able to adapt to situations and develop strategies and goals. It is also relevant in the expression of language, due to the important role of Broca’s area.
2. Parieto-temporo-occipital association area
This association area is located between the temporal, parietal and occipital lobes, integrating different information from senses such as vision, touch and hearing. This associative area is fundamental for human beings, since it is largely thanks to it that we link data from different perceptual pathways.
It allows symbolism, interpretation and understanding of reality as a whole. Also allows conscious perception and orientation Thanks to it (specifically the one located in the left hemisphere) we are also able to interpret both oral and written language.
The limbic cortex is the third of the large multimodal association areas. Information from the limbic system is integrated in this associative cortex. It allows us to understand our emotions and associate them with specific aspects of reality, as well as the link between these and memories. It also influences the capture of emotions in others.
Effects of damage in these areas
The effect of an injury or an alteration of any of these areas can have various effects of varying intensity and severity, altering our behavior and perception.
Lesions in unimodal association areas will cause difficulties in the recognition of stimuli, generating agnosias. That is to say, we see something but we don’t know what it is, or we touch something but cannot determine what it is. With regard to injuries in motor association areas, specifically in the supplementary motor area, it tends to generate incoordination and apraxia so that the monitoring of actions that require sequenced movements will be profoundly affected, being minimal or non-existent.
When it comes to injuries in multimodal association areas, damage can affect a large number of complex mental functions and processes. If the language areas are damaged, aphasias will occur (especially those in which there are comprehension problems). In the case of the prefrontal, Damage to this area can alter personality and self-management of the person, causing everything from disinhibition and aggressiveness to the inability to maintain concentration, set goals or follow plans.
Regarding the associative cortex, emotional expression may be made difficult or impossible or the capture of it in others, as well as detaching the emotion from the stimulation that is being received.
